Cam shaft



Dec. 9, 1924- 1,518,499

J. GARLICK CAM SHAFT Filed May 2. 1921 I if% Patented Dec. 9, 1924.

UNITED .STATES PATENT OFFICE,

JEW GARLICK, 0F PATERSON, NEW JERSEY.

CAM SHAFT.

Application filed May 2,

son, in the county of Pass-aic and State of' New Jersey, have invented anew and useful Cam Shaft, of which the following is a specification.

This invention aims to provide novel means for imparting rotation to thevalve stem of an internal combustion engine.

Generally-stated, a cam may be located 111 three different ways withrespect to the axis of rotation of a valve stem. First, the cam may beso placed that it is symmetrical with respect to the axis of thevalve'stem. This construction has no bearing on the present invention,because it produces no rotation of the stem, and, consequently, nogrinding of the valve, and no cleaning of the valve of carbon, or likedeposits. Second, thecam may be located more or less at one side of theaxisof the stem. This construction has a bearing on the presentinvention, because a rotation of the valve stem results. Theconstruction alluded to, however, is unsatisfactory and undesirable,because if the entire periphery of the cam exerts a pressure on thestem, the right line sliding movement of the stem is interfered with,and there is a continuing force tending to cause the stem to reciprocateat an acute angle to the cam shaft, the result being increased friction,wear on the valve stem, and wear on the opening wherein the stemreciprocates. A third construction, and the one which characterizes thisinvention, embodies a cam, located symmetrically with respect to thevalve stem, and trimmed off, at the point or highest portion of the cam,to define a projection which engages the stem at one side of the axis ofthe stem, the cam exerting a direct thrust on the stem, throughout themajor portion of the periphery of the cam, and exerting a rotatingaction only whilst the comparatively small projection, formed by cuttingawa the highest part of the cam, .is engaged wit the stem, at one sideof the axis of the stem.

Within the scope of what is claimed, a mechanic may work changes in thestructure shown and described, without departing from the spirit of theinvention,

1921; seria No. 466,160.

In the drawing :Figure 1 shows in elevation, a device constructed inaccordance with the invention; Figure 2 is a sectional detail whereinthe cam is viewed at right angles to the showin of Figure 1.

Referring to the rawing the numeral 1 denotes a support, in the form ofa portion of the valve chamber of an internal combustion engine, theseat appearing at 2, the numeral 3 denoting a boss wherein a stem 4 ismounted for right line reciprocation, the stem carrying a valve 5cooperating with the seat 2. Although the invention may be used inconnection with tappets, an extremely simple construction has beenshown, a head 6 being mounted directly on the stem 4, the termvalve-operating member being used hereinafter to cover any kind of anelement whereby a valve may be carried, unseated or otherwisecontrolled.

A cam shaft is shown at? and carries a cam 8. The cam 8 is disposedsymmetrically with respect to the axis of the stem 4. The cam 8 is cutaway, as shown at 9, at the highest point of the cam, and throughout aminor and exceedingly small portion of the periphery of the cam, todefine a projection 10, located unsymmetrically with respect to the axisof the stem 4. In practice, the cam 8 may be cut away at 9, oneone-thousandth of an inch, more or less, the decimal mentioned being asatisfactory embodiment, and rendering it clear that the amount of thecam which is cut away need be but very small. The result of theoperation of a cam, constructed as described, is that, throughoutpractically all of the rotation of the cam, the cam will exert astraight line thrust on the valve, no rotation being imparted to thevalve, and there being no tendency to produce Wear or friction. When,however, the small projection 10 cooperates with the part 6 or itsequivalent, the valve is rotated.

The valve spring 16 may exert a-thrust at one or both ends onanti-friction devices 17 cooperating, respectively, with the part 1 ofthe valve chamber and with the element 6.

Because the straight bearing edge of the projection 10 extends to apoint closely adjacentto the periphery of the head 6, the projectionwill have a maximum tendency to rotate the o crating member, 4-6, andbecause the sai edge extends to a point in direct alinement with thestem 4, the projection will have a minimum tendency to push the stem outof alinement.

I claim In a device of the class described a valve operating membercomprisin a stem and a. head on the stem, a shaft located symmetricallywith reaspect to the axis of the stem and substanti 1y equal in width tothe diameter of the head, a portion of the high end of the cam being cutaway to form a projectlon disposed unsymmetrically with respect to theaxis of the stem, the projection having a straight bearaving a cam.

infi edge located at right angles to the stem an extending radially ofthe head from a point in direct alinementiwith the stem to a pointclosely adjacent to the periphery of the head, the projection having amaximum tendency to rotate the operating member, and having a minimumtendency to push the stem out of 'alinement.

In testimony that I claim the foregoing as my own, I have hereto afiixedmy signature in the presence of two witnesses.

4 JEW GARLICK.-

Witnesses:

LESTER A. DE Von,

W. A. HARRISON.

